Roof problem - mystery lines

[tim.101799]

I am trying to model a fairly complicated slopped roof by foot print and I am having some issues. The roof assembly is 12” rafters, ¾” plywood, shingles, and the edge condition of the roof is set to 2 cut plumb with an 8” fascia. After I sketch the roof, Revit adds some mystery lines to the 3D geometry that shouldn’t be there. Through trial and error I discovered that if I set the roof to plumb cut, the mystery lines go away and two cut square they come back. Has anyone else had a problem like this?

While creating the attached images I played around with the fascia depth on the 2 cut plumb roof. I changed it from 8” to 12” and still have the lines. Changed it to 14” and the lines go away. So it seems to be an issue with the fascia.

[tim.101799]

Kind of a cheat, but if i change the thickness of the structure to 6" the roof will work with an 8" fascia

[patricks]

Are those lines visible in all views, from all angles, 3D, plan, etc?

I wouldn't cheat the roof structure depth, because then it will be much more difficult and confusing when trying to set the roof to the correct height.

Can you copy out the roof and surrounding walls to a blank file and post it here?

[tim.101799]

Are those lines visible in all views, from all angles, 3D, plan, etc?

I wouldn't cheat the roof structure depth, because then it will be much more difficult and confusing when trying to set the roof to the correct height.

Can you copy out the roof and surrounding walls to a blank file and post it here?

yes, those lines show in all view. I will copy those elements to a clean file and post it here in a few.

[tim.101799]

Attached is the test file you asked for. There are 3 examples

When looking at them in elevation from left to right they are:

1. 6” structure, 2 cut plumb roof with 8” fascia….no lines
2. 12” structure. Plumb cut………..no lines
3. 12” structure, 2 cut plumb with 8” fascia……..mystery lines


file is in R2010, but I also tried in R2011 and had the same issue

[DoTheBIM]

Your first two examples are essentially the same thing. both plumb cut. shorten the facia hieght to 6" on the first example and then you'll have a two cut plumb. and thus the same problem. Revit is confused by how you layed out your sketch lines when it comes to the intersection of the bottom side of front roof plane and where it meets the eaves. in the middle of the roof. You could play with the length of where you have that valley defined (but this will not be precise) or just make the roof in two halves and join them together (which is what I'd do). Actually I'd make one half, group it and then mirror it. That way if one half changes the other half will update.

[tim.101799]

Your first two examples are essentially the same thing. both plumb cut. shorten the facia hieght to 6" on the first example and then you'll have a two cut plumb. and thus the same problem. Revit is confused by how you layed out your sketch lines when it comes to the intersection of the bottom side of front roof plane and where it meets the eaves. in the middle of the roof. You could play with the length of where you have that valley defined (but this will not be precise) or just make the roof in two halves and join them together (which is what I'd do). Actually I'd make one half, group it and then mirror it. That way if one half changes the other half will update.

I tried modeling only half of the roof when I first encountered this problem, still got the mystery lines. Thats when I started playing around with the fascia heights and roof edge condition.

[Elmo]

Not sure, but if you click on the align eaves command there seems to be a few issues there. I would suggest looking at that first and see if this doesn't resolve it.

[DoTheBIM]

I tried modeling only half of the roof when I first encountered this problem, still got the mystery lines. Thats when I started playing around with the fascia heights and roof edge condition.
Ah.. you're right... didn't think about the eave through the valley still running a muck with the front roof plane. How will the rain drain from that valley?

[tim.101799]

Ah.. you're right... didn't think about the eave through the valley still running a muck with the front roof plane. How will the rain drain from that valley?

Not 100% sure yet, this is still just the design concept model. off the top of my head I guess I would build a cricket in the valley to divert water to the front and rear.

[DoTheBIM]

If you have to have the structure included in the roof definition I think you're going to have to build it in 3 parts. 1 for each peak down to valley (2 parts) (both plumb) and then one to wrap around and define your double cut plumb.

We don't model the structure in our roofs, because usually the structure is never the same depth as the outside finishes (for gable end exposure). We just model the top side finish and let it go plumb.

[tim.101799]

We don't model the structure in our roofs, because usually the structure is never the same depth as the outside finishes (for gable end exposure). We just model the top side finish and let it go plumb.

thats not a bad idea! I may give that a shot and see how it works out for this project.